The trial of a senior Scotland Yard police officer accused of offering to sell information to the now defunct News of the World was briefly halted on Monday afternoon after the defendent broke down in tears in the dock.

The jury was hearing how Metropolitan police detective chief inspector April Casburn had concerns about her working environment – she did not have her own office for two years, even though detective constables under her command did.

Spotting her "in distress", the judge asked her solicitor to go into the dock to ask her whether she was fit to continue with the trial at Southwark crown court in central London.

After regaining her composure, her manager, detective superintendent Christos Kalamatianous, continued to testify.

Kalamatianous admitted that Casburn had raised concerns with him about what she perceived to be his "intrusive" style of management.

Occasionally, he signed his texts off with a capital X or sometimes a small x, which he said was "a cordial sign off, a kiss". He denied his relationship with Casburn was hostile, even after she had raised concerns about his management style. He said he had felt that he had come to an understanding with her.

Texts between Kalamatianous and Casburn were read out in court in which he expressed support for her when she had to go to the doctor and when she had completed the process for a proposed adoption of a child.

Also testifying was Dean Haydon, the senior investigating officer on Operation Varec, the Scotland Yard investigation set up following the publication of an article on phone hacking in the New York Times on 1 September 2010.

Haydon challenged Casburn's claim that she had phoned the News of the World because she was concerned public resources were being diverted from counter terrorism into the phone-hacking investigation.

He told the court he selected a financial investigator from Casburn's team because her detectives and analysts would have been through a more stringent vetting procedure than many other officers and his investigation was sensitive, with information distributed "on a need-to-know" basis.

But Haydon said the work required by his investigation was minimal and could have been "absorbed" in "business as usual" and denied he would have drained resources from counter-terrorism operations.

All the financial investigator was asked to do was match the bank account address with the addresses of six individuals named in the New York Times article on alleged phone hacking at the News of the World, he said.

Being cross examined by counsel for Casburn, Haydon admitted that all six people he was investigating had been named in the New York Times article.

The trial continues.

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